Development of a Porcine Slaughterhouse Kidney Perfusion Model

Machine perfusion techniques are becoming standard care in the clinical donation and transplantation setting. However, more research is needed to understand the mechanisms of the protective effects of machine perfusion. For preservation related experiments, porcine kidneys are acceptable alternatives to human kidneys, because of their size and similar physiology. In this experiment, the use of slaughterhouse kidneys was evaluated with normothermic kidney perfusion (NKP), thereby avoiding the use of laboratory animals. Porcine kidneys were derived from two local abattoirs. To induce different degrees of injury, different warm ischemic times and preservation techniques were used. After preservation, kidneys were reperfused for 4 h with two different NKP solutions to test renal function and damage. The effect of the preservation technique or a short warm ischemic time was clearly seen in functional markers, such as creatinine clearance and fractional sodium excretion levels, as well as in the generic damage marker lactate dehydrogenase (LDH). Porcine slaughterhouse kidneys are a useful alternative to laboratory animals for transplantation- and preservation-related research questions. To maintain kidney function during NKP, a short warm ischemic time or hypothermic machine perfusion during the preservation phase are mandatory.

Advances in Hypothermic and Normothermic Perfusion in Kidney Transplantation

Hypothermic and normothermic machine perfusion in kidney transplantation are purported to exert a beneficial effect on post-transplant outcomes compared to the traditionally used method of static cold storage. Kidney perfusion techniques provide a window for organ reconditioning and quality assessment. However, how best to deliver these preservation methods or improve organ quality has not yet been conclusively defined. This review summarises the promising advances in machine perfusion science in recent years, which have the potential to further improve early graft function and prolong graft survival.

Effectiveness Assessment of a Modified Preservation Solution Containing Thyrotropin or Follitropin Based on Biochemical Analysis in Perfundates and Homogenates of Isolated Porcine Kidneys after Static Cold Storage

In this paper, we assess the nephroprotective effects of thyrotropin and follitropin during ischaemia. The studies were performed in vitro in a model of isolated porcine kidneys stored in Biolasol (FZNP, Biochefa, Sosnowiec, Poland) and modified Biolasol (TSH: 1 µg/L; FSH 1 µg/L). We used the static cold storage method. The study was carried out based on 30 kidneys. The kidneys were placed in 500 mL of preservation solution chilled to 4 °C. The samples for biochemical tests were collected during the first kidney perfusion (after 2 h of storage) and during the second perfusion (after 48 h of storage). The results of ALT, AST, and LDH activities confirm the effectiveness of Biolasol + p-TSH in maintaining the structural integrity of renal cell membranes. Significantly reduced biochemical parameters of kidney function, i.e., creatinine and protein concentrations were also observed after 48 h storage. The protective effect of Biasol + p-TSH is most pronounced after 2 h of storage, suggesting a mild course of damage thereafter. A mild deterioration of renal function was observed after 48 h. The results of our analyses did not show any protective effect of Biolasol + p-FSH on the kidneys during ischaemia.

Ex vivo analysis of graft viability using 31P magnetic resonance imaging spectroscopy

Objective Expansion in organ supply has been proposed through the use of organs after circulatory death (donation after circulatory death [DCD]) in order to face the chronic shortage of kidneys for transplantation. However, many DCD grafts are discarded because of long warm ischemia times, and the absence of reliable non-invasive means to determine kidney viability. P magnetic resonance imaging (pMRI) spectroscopy is a noninvasive method to detect high-energy phosphate metabolites, such as ATP. However, the reliability of pMRI to predict kidney energy state, and its viability before transplantation remain also unknown. Methods To mimic DCD, pig kidneys underwent 0, 30 min or 60 min of warm ischemia, before oxygenated hypothermic machine perfusion (HMP). During the ex vivo perfusion, we assessed energy metabolites and Gadolinium elimination using pMRI. Each sample underwent histopathological scoring. Results Using pMRI, we found that in pig kidney, ATP was rapidly generated in presence of oxygen (100 kPa), which remained stable up to 22 h. Warm ischemia (60 min) induced significant histological damages, delayed cortical and medullary Gadolinium elimination (perfusion), and reduced ATP levels, but not its precursors (AMP). Finally, ATP levels and kidney perfusion both inversely correlated with the severity of kidney histological injury. Conclusion ATP levels, and kidney perfusion measurements using pMRI, are biomarkers of kidney injury after warm ischemia. Future work will define the role of pMRI in predicting kidney graft viability and patient's survival.

Hydrogen sulfide (H2S) reduces oxygen and ATP consumption in the isolated perfused pig kidney

Objective Organ donation after circulatory death [DCD] has the potential to reduce the shortage of kidneys available for transplantation. However, many DCD grafts are discarded because of long warm ischemia times. Strategies reducing oxygen demand may minimize damages caused by ischemia/reperfusion injury. Ex-vivo, Hydrogen sulfide (H2S) reduces oxygen and ATP consumption of the isolated perfused kidney, reduces inflammation and improves renal function following ischemia reperfusion injury in rodents. However, the benefits and applicability of H2S in clinically relevant model remain unknown. Methods To mimic DCD, pig kidneys underwent 0 or 60 min of warm ischemia, before oxygenated hypothermic machine perfusion (HMP). NaHS (100µM), an H2S donor, was added to the perfusion media or injected as an intra-arterial bolus before warm ischemia. After 2 hours of HMP, kidneys were transplanted and reperfused for 1 hour before harvest. Kidney function was assesses before, after and during ex vivo perfusion by measuring energy metabolites, Gadolinium elimination by pMRI and histopathological scoring. Results Warm ischemia (60 min) induced significant histological damages, delayed cortical and medullary Gadolinium elimination (perfusion), and reduced ATP levels, but not its precursors (AMP). As expected, ATP levels and kidney perfusion both inversely correlated with the severity of kidney histological injury. NaHS reduced metabolism during warm ischemia, and seemed to increase kidney ATP levels and viability after reperfusion. Conclusion Our preliminary data suggest that the H2S donor NaHS reduces kidney metabolism and protects from warm ischemia. Further experiments will identify the best administration protocol and the clinical relevance of H2S supplementation in the context of organ preservation.

Vasodilatory shock in 15 years old girl in Bulgaria

Background Multisystem Inflammatory Syndrome in children related to COVID-19 (MIS-C) is a new condition the aftermath of which is yet to be studied both in Bulgaria and globally. Up to mid December 2020, world COVID-19 fatalities are put at 1 582 674, according WHO statistics. Case Presentation Summary We present a 15 years old patient with MIS-C, diagnosed with acute abdomen, operated andtreated for septic shock syndrome. The current situation represents a major clinical challenge in part due to the complex differential diagnosis involved: acute abdomen, septic shock, autoimmune diseases (Lupus erythematosus, Juvenile idiopathic arthritis, Kawasaki disease, Acquired immune deficiency, Crohn`s disease, Ulcer colitis), acute myocarditis. At the same time, other symptoms observed in children with COVID-19 such as skin rashes, lymphadenopathy, conjunctivitis are not presented inour patient. We did not observe any myocardial injury, however she went into an acute vasodilatory shock with tachycardia, reduced kidney perfusion pressure and oliguria. Learning Points/Discussion Effects of SARS-CoV-2 infection on patients will be asubject of analysis and clinical research. Differential diagnosisof the multisystem inflammation syndrome in children, clinicalexperience and newtherapeutic strategies are the key to reducing mortality and long-term complicationsin the affected patients.

SARS-CoV-2-Associated Nephropathy: Direct Renal Infection and Damage

Acute kidney injury is a frequent complication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), principally because of hypotension and decreased kidney perfusion secondary to haemodynamic or haemostatic factors, drug-induced nephrotoxicity, and cytokine storm syndrome related to sepsis. Additionally, several factors support the existence of SARS-CoV-2-associated nephropathy, such as early, new-onset proteinuria and haematuria in many patients, the identification of SARS-CoV-2 viral load in precisely defined kidney compartments, ultrastructural and immunohistochemical evidence of direct viral infection of the kidneys, and, most importantly, morphological alterations associated with cytopathic action induced by the virus. In addition, collapsing glomerulopathy that has been reported in patients of African American descent with underlying apolipoprotein L1 (APOL1) kidney risk alleles and SARS-CoV-2 infection is evidence of a distinct form of SARS-CoV-2-associated nephropathy, the APOL1-SARS-CoV2-associated nephropathy.